稀土元素对铝硅合金凝固的影响

The Rare Earth Element's Influence on the Solidification of Al-Si Alloy

针对铝硅合金半固态成形重熔工艺的要求,讨论了稀土元素对铝硅合金凝固的影响.实验结果表明:在AlSi7合金中加入一定量的稀土元素后,使铝硅合金凝固的固液两相温度区间加宽,固液两相区间从34℃增加到59℃,延长了凝固时间,使凝固时间从2280s延长到3060s.在不同实验条件下的金相组织表明,稀土元素还改善了铝硅合金晶体的形貌,细化了α相的晶粒并使条状共晶硅变为点状,这些有利于半固态成形技术的实现.

Based on the requirement of technique of Al - Si alloy semi - solid molding remelting, the influence of RE element on Al - Si alloy was discussed in this paper. And the results showed that when RE element was added into AlSi7 alloy ,the temperature range between solid and liquid of Al- Si alloy was widened ,it is augmented from 34 ℃ to 59 ℃ ,the time of solidification is added,from 2 280 s to 3 060 s,the appearance of grain is improved at the different conditions,the α grain is fined and the appearance of Si in the eutectic structure is changed from strip to point. All of these are favorable to realizing technology of semi - solid molding. Key Words： RE element ; semi - solid ; Al - Si alloy ; solidification.